This invention relates to a mechanism for operating shut-off members in gas turbine engines, more particularly in turbojet engines, where circumferential rotation of an actuating ring is converted into an axially directed opening or closing movement by the intervention of transmission elements.
A mechanism of this description can be used, e.g., on variable-cycle turbojet engines. Variable-cycle turbojet engines have the feature that their thrust and consumption characteristics can be varied within a certain range. Variation of these characteristics is in part achieved by varying the mass flows in the engine, e.g., by varying the division of the mass flow downstream of the low-pressure compressor into core and bypass flows by means of a variable flow divider, partly by varying variable compressor and turbine stators, and also by the admission or interruption of air flows. This last provision is used, e.g., for bleeding air from the core engine and ducting it into the bypass flow or for affecting the flow of afterburner cooling air.
Shut-off members of this type must often be arranged in engine areas affording little space for their operation, especially where axial motion of larger actuating members, such as actuating rings, is prevented. This is often aggravated by the fact that several such members must be actuated simultaneously. An important consideration with all arrangements is also that operation of the shut-off members should preferably not increase the outer diameter of the engine over that of an equivalent fixed-cycle engine and that the flow through the bypass duct should be disturbed as little as possible by detrimental fittings.
Accordingly, it is an object of the present invention to provide an operating mechanism of simple arrangement and moderate space requirement.
Another object of the present invention is to provide an arrangement of the foregoing character which may be economically fabricated and readily maintained in service.
A further object of the present invention is to provide an arrangement, as described, which has a substantially long operating life.